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How can I remove the unique option from a column in MySQL?


How can I remove the unique option from a column in MySQL?

By : Vitaliy Shopov
Date : November 21 2020, 07:01 PM
it helps some times I have a field in my db called "user" which is unique.
code :


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MySQL: How to alter varchar(255) UNIQUE column to UNIQUE Text NOT NULL?

MySQL: How to alter varchar(255) UNIQUE column to UNIQUE Text NOT NULL?


By : user2647505
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , Are you going to use TEXT column as part of UNIQUE KEY? It's VERY inefficient! Don't do that! I'm strongly suggest you to:
Add additional column named for example 'description_hash' char(32) not null default '' Store the hash-value for description field into it. For ex. description_hash=MD5(description) Change your key to UNIQUE KEY (name, description_hash)
MySQL handle duplicate key error insert into table with multiple unique indexes; not multi-column unique index

MySQL handle duplicate key error insert into table with multiple unique indexes; not multi-column unique index


By : Ani Tanev
Date : March 29 2020, 07:55 AM
I hope this helps . I found the answer under Which unique key is hit with my insert?. It is not ideal however does solve the problem.
The following is the applied solution:
code :
    ...
    DECLARE EXIT HANDLER FOR 1062 BEGIN
        -- Check if col1Value is already in use
        IF EXISTS (
            SELECT 1
            FROM tableName
            WHERE col1 = col1value
            LIMIT 1
        ) THEN
            SET errColName = 'Col1';

        -- Check if col2Value is already in use
        ELSEIF EXISTS (
            SELECT 1
            FROM tableName
            WHERE col2 = col2value
            LIMIT 1
        ) THEN
            SET errColName = 'Col2';

        -- Check if col3Value is already in use
        ELSEIF EXISTS (
            SELECT 1
            FROM tableName
            WHERE col3 = col3value
            LIMIT 1
        ) THEN
            SET errColName = 'Col3';

        END IF;
    END;
    ...
MYSQL SELECT unique values from column where column2 = value & count how many times each unique value was found

MYSQL SELECT unique values from column where column2 = value & count how many times each unique value was found


By : Đặng Tuấn Anh
Date : March 29 2020, 07:55 AM
fixed the issue. Will look into that further I am looking to select and count each occurrence of column phone_number where column2 email_eddress == value. , Below query should work:
code :
select sender_email, phone_number, count(*)
from some_numbers 
group by sender_email, phone_number;
How to remove unique option using sequelize

How to remove unique option using sequelize


By : Maxt
Date : March 29 2020, 07:55 AM
Does that help This is from the Sequelize documentation and allows you to change the meta data on a column:
code :
queryInterface.changeColumn(
  'nameOfAnExistingTable',
  'nameOfAnExistingAttribute',
  {
    type: Sequelize.FLOAT,
    allowNull: false,
    defaultValue: 0.0
  }
)
My Django manytomany fields are all marked unique, is there an option to remove this?

My Django manytomany fields are all marked unique, is there an option to remove this?


By : IckyBrrr
Date : October 21 2020, 11:12 AM
seems to work fine Given a model like this: , You can create a third table:
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